Crystal and molecular structures of two modifications of a chelate compound of Pb[(iso-C4H9)(2)PS2](2)

摘要

A chelate compound Pb[(iso-C4H9)(2)PS2](2) is synthesized. Using X-ray diffraction data, the crystal structures of two modifications of this compound are determined (X8 APEX diffractometer, MoK alpha radiation, 14169 F-hkl , R = 0.0480 for the low temperature alpha-form and 6261 F-hkl , R = 0.0387 for the beta-form studied at ambient temperature). The crystals are triclinic: a = 11.047(2) angstrom, b = 14.486(3) angstrom, c = 32.048(6) angstrom; alpha = 91.30(3)degrees, beta = 99.73(3)degrees, gamma = 101.61(3)degrees, V = 4942.9(17) angstrom(3), Z = 8, rho(calc) = 1.682 g/cm(3) (alpha-modification) and a = 11.2124(5) angstrom, b = 14.6989(7) angstrom, c = 17.1644(6) angstrom; alpha = 109.393(1)degrees, beta = 94.989(2)degrees, gamma = 101.649(1)degrees, V = 2576.83(19) angstrom(3), Z = 4, rho(calc) = 1.613 g/cm(3) (beta-modification), space group P (1) over bar for both polymorphs. The structures are molecular, coordination cores of PbS4 are tetragonal pyramids with Pb atoms in the vertices and S atoms in the base. In both structures intermolecular Pb center dot center dot center dot S contacts yield supramolecular ensembles comprising by four molecules, where PbS4+2 cores form planar aggregates of edge-sharing octahedra. The ensembles are joined by weak intermolecular S center dot center dot center dot S interactions resulting in the development of polymeric chains along the a axis.